In fig. REF  we plot
the absolute value \(|A|\)  of
the pump power dependence of the two sidebands fluxes measured at full noise power from NG. In strong contrast with the initial (no noise, full green line) situation, now the "redside" (yellow) and "blueside" (cyan) sideband signals do not coincide anymore. This phenomenon is known as "sideband asymmetry", and has been already discussed in the framework of quantum mechanics [1]}, [2]}.
Physically, it is due to the interference between the broadband microwave noise in the measuring (or output) port and the mechanically generated microwave noise in the sidebands; the sign of these correlations is reversed for these two (constructive or destructive interferences) [3]}.
